He said the “secure perimeter was outside the station entrance of the Navy Yard stop.

“The entrance has been reopened because it is believed to be safe to do so,” Stessel said.

Updated: 9:30 a.m.

Metro transit police said they sent transit police officers Monday morning to assist in an incident that involved a shooter at the Washington Navy Yard.

The Navy Yard Metro station is less than a mile from Navy Yard.

Metro spokesman Dan Stessel said transit officers were “sent as a precaution” as the incident unfolded just before 9 a.m.

Transit police officers were sent, he said, to “monitor [the Navy Yard] station and to ensure the safety of customers.”

As of 9:19 a.m, Metro had reopened the New Jersey Avenue entrance at the Navy Yard stop on the Green Line.

Metro had earlier closed the entrance of its New Jersey Avenue station at the Navy Yard stop, as police searched for a shooter at the Washington Navy Yard.

Officials at Metro said the shooter is not believed to be in the rail system but because of its “proximity to the scene,” Stessel said, the entrance is being closed. Riders should use the Half Street entrance.

Metro officials said some of its bus routes in the area are also being impacted by the police search around the Navy Yard. Bus routes are being rerouted around the area and may experience delays. Those routes include the following, A9, P6, V7, V9, 90 and 92.

Bus routes of the DC Circulator that also run along M Street are said to be experiencing delays because of the police activity.